1. Field of the Invention
This invention relates to projectile steering mechanisms and, more particularly, to a means for extending an elongated device into the slip stream of a projectile in order to provide steering forces.
2. Description of the Prior Art
Mechanisms for steering a missile or rocket during the flight thereof have long been available in the prior art. For example, U.S. Pat. No. 3,764,091 discloses a steering and propulsion system for a guided missile wherein a guidance head in the nose of the missile seeks out the target and gives continuous signal data in regard to the bearing of the target from the missile. From this and other information relating to the missile flight, control signals are derived for the application to servo-valves of on-board actuators for the purpose of continuously correcting the missile flight to ensure interception of the target by deflections of the fin and deflector nozzle assembly.
Projectiles which have means associated therewith for reducing drag or for stabilizing the projectile after it has been fired are also well known. For example U.S. Pat. No. 656,933 discloses a projectile having a stem portion retracted before firing, which extends from the rear of the projectile after firing and thereafter acts as a drag to cause the projectile to travel nose foremost, thus acting to stabilize the projectile. Means for steering the projectile after firing are not provided, however.
U.S. Pat. No. 2,359,515 discloses a projectile of substantially smaller diameter than the bore of the gun and provided with a tail fin assemblage of fixed fins which is fully extended after firing and acts, inter alia, to increase the steering force leverage on the projectile.
U.S. Pat. Nos. 1,384,868 and 1,537,713 both disclose a bomb adapted to be dropped from an aircraft, the bomb including a controllable drag rudder mounted on an extension fixed rigidly to the bomb. A control element allows the drag rudder to be deflected, thus enabling the bomb to be steered after it is dropped.
U.S. Pat. No. 2,432,421 discloses a bomb having a rear rudder, the angular position of which can be changed only once. The rudder is coupled to an internal lever, the lever being caused to pivot upon receipt of a radio signal. Movement of the lever causes the rudder to be angularly displaced, whereby the bomb travel changes from a vertical descent to a horizontal motion.
Other prior art patents which disclose means for controlling some characteristics of a bomb, missile, rocket or the like are:
U.S. Pat. No. 3,713,607 discloses a spike on the front end of a missile. The spike, a hollow tube, is not for control purposes but used for reducing drag on the missile.
U.S. Pat. No. 3,412,962 discloses an air drag reducing attachment for the rear end of an aircraft and includes a plurality of elongated concentrically nested and relatively telescopingly engaged tubular members.
U.S. Pat. Nos. 1,278,786; 3,292,879; 3,888,175; 3,267,854; 4,228,973; 1,324,433; 2,976,805; 2,589,129 and French Pat. No. 492,123 show various means for stabilizing an in-flight object.
U.S. Pat. Nos. 3,179,052; 2,297,130; and French Pat. No. 1,459,354 disclose mechanisms for reducing drag on an in-flight object.
Although the aforementioned examples of prior art disclose various ways for controlling the drag, stabilizing and steering characteristics of a launched, airborne object, it would be desirable if a simple technique for accurately steering a projectile fired by a gun could be provided. Since the powder charge initially carried with the projectile is in the cartridge shell, the steering mechanism also will be subjected to space and temperature constraints, and thus would have to be operable in that environment.